Aircraft have multiple seats, lavatories, and galleys disposed in a space limited by the fuselage.
Various proposals have been made for the sake of increasing the number of seats.
For example, US Patent Publication Nos. 2008/0179456A1 and 2009/0283636A1 disclose movable aircraft lavatory units, and propose aircraft lavatory units having layouts able to be altered.
Nevertheless, even if the layout of aircraft lavatory units is altered, the area they occupy remains unchanged, and thus there are limitations to any expansion in the number of seats.
In many cases, the lavatories inside of aircraft lavatory units, in addition to toilets, are provided with wash basins having bowls and compartments for lavatory toiletries, but these bowls and compartments protrude on the sides of the lavatories from the wall parts partitioning them.
Thus, depending on the mutual positional relationship of the toilet, bowl and compartment, the bowl and compartment may become an obstruction and make it difficult to sit upon the toilet seat.
However, if the bowl and compartment are simply disposed farther away from the toilet, the width and depth of the aircraft lavatory unit are enlarged, which is disadvantageous to increasing the number of seats.